Results
In all of the subjects, there was demonstrated severe baseline airways obstruction (Table 1). Subjects with COPD exhibited a significantly greater degree of baseline airways obstruction (p<0.05) than those with asthma. The HHN treatment resulted in a greater improvement in FEV, than MDI-spacer for the combined group of subjects and the subgroup with asthma when the data are expressed as percentage of change after metaproterenol (Fig 1). In the subgroup with COPD, the HHN treatment resulted in a significantly greater percentage of change increase in FVC when compared with MDI-spacer.

When the data are reported as absolute improvement, that is the absolute difference between the before and after metaproterenol spirometry, this same pattern was observed. The HHN metaproterenol resulted in a significantly greater absolute improvement than MDI-spacer in FEV, for the combined group of subjects (p<0.05) (0.20±0.05 L for HHN) vs (0.06±0.03 for MDI-spacer), a significantly greater improvement in FEV, for the subgroup with asthma (p<0.02) (0.27 ±0.07 L for HHN) vs (0.03±0.05 L for MDI-spacer), and a significantly greater improvement in FVC in the subgroup with COPD (p<0.05) (0.28 ±0.10 L for HHN) vs (0.08±0.06 L MDI-spacer).

Figure 1. Mean percentage of change from baseline in FVC and expiratory flow rates for combined group of all subjects and subgroups with asthma and COPD. Asterisk = p<0.05.